\documentclass[a4paper, 12pt]{article}

\usepackage[margin=1.5cm]{geometry}
\usepackage{fancyvrb}

\title{ID on UNIX System}
\author{Chen Rushan\\chenrsster@gmail.com}
\date{2009.08.09 8:15}

\begin{document}

\maketitle

Basically, there're 8 types of ID on a general UNIX system, they all represent
different things, but they're all valid IDs existing on the system which can be 
found in file \verb=/etc/passwd=. Here is a list of all these types:
\begin{enumerate}
   \item file owner
   \item file group owner
   \item process real user ID
   \item process real group ID
   \item process effective user ID
   \item process effective group ID
   \item process saved set-user-ID
   \item process saved set-group-ID
\end{enumerate}

From above list, it's obvious that the first 2 of them have to do with files, and
the following 6 with a running process.

\end{document}
